Fireproof floor



(No Model.) 1

A. L. JOHNSON. FIREPROOF FLOOR.'

Ndjsom?. Patented Nov. 19,1895.'`

ANDREW [LGHANANL PHDTO-LITHO-WASHINGYDNAD-C UNITED. STATES PATENT OFFICE.v

ALBERT L. JOHNSON, or sT. LoUIs, MISSOURI.

FIREPROOF FLOOR.

SPECIFICATION forming part of IJetters Patent No. 550,177, dated November 19, 1895.

Application filed ASeptember 5 1895. Serial No. 561,542. (No model.)

T0 all whom it may con/cern:

Be it known that I, ALBERT L. JOHNSON, residing in the city of St. Louis, State of Missouri'7 have invented a new and useful Fireproof Floor, of which the following is a specication.

My invention relates to concrete ioors, and has for its principal objects to increase the strength and rigidity of such floors and reduce the cost of making them.

It consists in the arrangements and in the combinations 4of parts hereinafter described and claimed.

In the accompanying drawings, Figure l is a cross-sectional view of my construction on the line 1 l of Fig. 8, with the top iooring mounted thereon. Fig. 2 is a cross-sectional view on the line 2 2 of Fig. 3, showing the suspensionstrap and rib in elevation and with the top flooring removed.' Fig. 3 is a plan view of the construction shown in Fig. 2 with the concrete partially broken away to show the expanded metal sheet. Fig. 4 is a perspective detail of the Aexpanded metal, and Fig. 5 is a sectional detail through the concrete and expanded metal.

The main support of my floor consists of parallel I-beams l, supported by the frame of the building. Over the tops of adjacent beams are fastened the ends of strong suspension straps or saddles 2,preferably of wrought-iron or steel and thin enough to be quite exible. The ends of these straps 2 extend beyond the farther edge of the beams and are bent to conform to tbe shape of the beam, so as to lie close against the same, while the middle portion of the strap or saddle bends or curves down. The curvewhich a exible hat wrought-iron or steel strap naturally assumes when its ends are supported at fixed points nearer together than'the length of the strap is the line of stable .equilibrium of such strap for supporting a vertical load distributed like a concrete floorthat is, the application of the concrete ,door on such a strap does not tend to change the form of its curve, but produces a tensile stress only therein. Upon each of these straps or saddles 2 as a bottom plastic concrete is filled in up to the horizontal level desired, so as to constitute a stiffening or strengthening rib 3. Upon the tops of the several ribs 3, extending from one rib to another, are laid bars or strips of metal, preferably sheets of expanded metal 4. The I-beams of concrete floors are generally protected from fire by having concrete haunches 5 built up on their lower ianges. In my construction the tops of these haunches are level with the tops of the ribs 3 and serve also to support 'the expanded metal 4, which extends sidewise beyond the ends of the ribs 3 to rest on said haunches, the expanded metal being cut to straddle the suspension-straps.

Upon the expanded metal is laid plastic concrete 6 to any desired thickness, and upon this layer of concrete 6 is laid any desired kind of flooring 7.

In making my door the suspension-straps 2 are vfirst iitted over adjacent I-beanis and adj usted parallel at the proper distance apart. Then suitable false work is built up to form side boxing for the strengthening-ribs 3 and haunches 5 and also to form a bottom for supporting the expanded metal 4, said bottom being flush with the tops of said ribs 3. The plastic concrete is then filled in such boxings to form the ribs and haunches, and then the expanded metal is laid on the tops thereof. Then the main layer of concrete 6 is laid upon the expanded lmetal 4 and worked through the interstices therein, so as completely to fill the same, the false work supporting the expanded metal and preventing waste of concrete. When the concrete hardens, the false work is removed.

On account of the interstices of the expanded metal being lled with concrete its tensile strength is very great. Other materials, such as strips of woven wire, may be substituted for expanded metal with fair results; but on account of the peculiar formation of expanded metal it has special advantages of its own.

l. A floor consisting of beams, suspension straps fastened at the tops thereof and curved down in the intermediate portion in the line of stable equilibrium, concrete ribs on said straps, strips of metal on said ribs and a layer of concrete on said strips, substantially as described.

2. A floor consisting of beams, suspension straps fastened at the tops thereof and curved down in the intermediate portion in the line of stable equilibrium, concrete ribs on said IOO straps, sheets of expanded metal on said ribs and a loyer of eouerete on said expzmded metal, snbstzrntiadly ns described.

3. A floor consisting of flanged beams, suspension straps luwing their ends fastened :Lt the tops thereof and Curved down in. the nterlnedote portion in the line of stable equi- ]brinnneonerete ribs on said straps, han nehes on the zLnges of said beznns, sheets of expanded metal on, said ribs and lmnnehes, and 1o :L layer of eouerete on said expanded metal, snbsmnizdy as described.

A. L. JOHNSON. Inv presence of- JAMES J'. ODoNonoE, JAMES A. CARR. 

